EPA Tier 4 emission standards have driven diesel engine manufacturers to develop various methods and processes to achieve compliance. Some of these compliance methods have increased engine heat energy rejection. Discharge gas recirculation is the main supply of additional heat energy. The discharge must be cooled before re-introduction to the intake manifold. Additionally as self-propelled sprayers get larger, the power requirements to operate the spray systems and other accessories have correspondingly increased. To meet these increasing power requirements, engines in self-propelled sprayers are also getting larger. Larger engines require larger engine-cooling systems to deal with the additional heat created by the larger engines. Heat radiated directly from these larger engines and heated air that is produced by pulling air across the radiator with a tan can together contribute to high engine compartment temperatures. High temperatures and airflow in the engine compartment cause heating of the various components as well as the engine itself Additionally, heated an in the intake system and an cleaner box changes air density and compromises engine performance and effects emissions.